1. `Field of Invention
This invention relates to heating systems with a thermal pump, including an evaporator section formed by a piping network buried in the ground, a compressor for compressing the evaporated working fluid and a condensing section operating as heating plant.
2. Description of Prior Art
The construction of heating systems with a thermal pump are well known to persons skilled in the art. Such construction is substantially similar to the construction of a refrigerating apparatus, with the exception that the process operates at a different temperature level. The working fluid, e.g., "Freon 12" evaporates at the ambient ground temperature and thereby extracts the desired quantity of heat thereof. The evaporated working fluid gets compressed thereafter to an elevated pressure and discharges in a downstream following condensing section heat to a heating system by extracting the heat of vaporization from the vapor. A heating system with a thermal pump has been disclosed, for example, in the journal "Elektrowaerme International" 30 (1972) Al-January. It has been proven that it is possible, depending on the condition of the ground, to extract during a uninterrupted operation in the winter season 20-30 kcal/hour sq. meter from the ground. Because the ground freezes up to a depth of about 70 centimeters, it is common practice to bury the piping network forming the evaporator section to a depth of 1 meter which necessitates substantial work and expenditures. The heat quantity which can be hourly extracted per square meter depends on the heat drop between the ground temperature and the evaporation temperature of the working fluid, and it has been found that due to the thermal conductivity of the ground the distance between adjacent pipes of the conduit network of known heating systems with a thermal pump must be at least 1 meter. In order to sufficiently heat, for example, a one family house by extracting heat from the ground an accordingly rather large section of the ground must be provided with pipes forming the conduit network.
One object of the invention is to provide a heating system with a thermal pump having an improved output.
A further object is to reduce the work and expenditures arising from installing the conduit network in the ground.
A heating system with a thermal pump in accordance with the invention includes a translucent screen shielding the ground from the atmosphere, such that a heat storage of the heat radiated from the sun and penetrated through the screen is provided and that the space defined between the ground surface and screen forms and insulation against heat loss to the atmosphere.
Accordingly an inventive heating system provides for a substantially higher temperature of the ground thus allowing an increased extraction of heat per unit area and reducing the distance between adjacent pipes of the conduit network to about 50 centimeters. Furthermore, the placing of the pipes in the ground can take place by simply forming separate narrow trenches by means of a ground mill or trench digger, in contrast to the prior art according to which the depth of the conduit network calls for the removal of earth to a depth of 1 meter.